Hi Eli,


> Is this with or without the patch I sent?
>

It is with the patch (in the two profiler.el reports, the "kill" hooks are
not present)


>
> > 1. The hooks are not called initially, I am not sure what triggers them.
> This makes the json parsing extremely
> > slow(100 times)
>
> The hooks are not called when decoding strings uses a fixed working
> buffer that is created once and never killed.  Then something in your
> setup causes this single working buffer to become in-use, and Emacs
> then allocates an additional buffer, which is created and killed each
> time we need to decode a string.  Both creating and killing of that
> buffer runs the buffer-list-update-hook.
>

Just found that it is not my setup which triggers the issue bug pressing
C-g during the parsing:

To reproduce:

(benchmark-run 10 (json-parse-string json-string))
(benchmark-run 10000000 (json-parse-string json-string))
(benchmark-run 10 (json-parse-string json-string))

Press C-g when second benchmark-run is processed.


> > 2. Even without the hooks, the JSON parsing is slower than the emacs -q
> native parsing when I am running
> > my setup. This will require additional investigation.
>
> Please, let's first finish fixing the factors we do understand already
> and see what effect that produces.  Otherwise I don't see how we can
> make steady progress in this matter.  That is why I sent an initial,
> most probably incomplete patch.  Please apply it and see what it fixes
> and what it doesn't fix.
>


I did exactly what you are saying here: I applied the patch and listed the
effects:
1. The buffer-list-update-hook is called
2. The patch does not affect the perf difference between emacs -q and my
setup.

> I must rely on you in this matter, because I cannot reproduce the
> slowdown on my system.

I realize that and I am trying to be as helpful as possible by sharing all
my observations.

Thanks,
Ivan